A heating element has a resistance of 100 Ω at room temperature. When it is connected to a supply of 220 V ,…

A heating element has a resistance of 100 Ω at room temperature. When it is connected to a supply of 220 V, a steady current of 2 A passes in it and temperature is 500 oC more than the room temperature. The temperature coefficient of resistance of the heating element is
  1. 5 ×10-4  oC-1
  2. 2 ×10-4  oC-1
  3. 1 ×10-4  oC-1
  4. 0.5 ×10-4  oC-1

Solution

Resistance of heating element after temperature increases by 500 oC=2202=110 Ω (from Ohm's law). The new resistance is related to the temperature coefficient of the heating element as 110=100 (1+α500)

α=10100 ×500α=2 ×10-4 °C-1

Asked in: JEE Main 2018 (16 Apr Online)

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